Incompatibility between new and existing products is a major problem in many technical disciplines including networking and signal switching. Often new products are developed having increased data rates but customers have invested heavily in legacy products operating at a slower data rate.
For example, many routing platforms have slots for WAN (Wide Area Network) Interface Cards (WICs) that provide interfaces between the routing platform and wide area networks.
The legacy WICs were conceived several years ago, and originally targeted PHY devices with a maximum bit rate of a few Mbps. Since then, the explosion of the internet and broadband availability has enormously increased the speed and complexity required of Cisco router interfaces. There is a need to expand the legacy WIC functionality to enable existing routing platforms to continue to meet present as well as future interface card requirements.